thank you very much for your reply.
Darren Hart writes:
On Fri, Nov 28, 2014 at 03:20:50PM +0100, Peter Feuerer wrote:
acerhdf has been doing an on-off fan control using hysteresis by
post-manipulating the outcome of thermal subsystem trip point handling.
This patch enables acerhdf to use the bang-bang governor, which is
intended for on-off controlled fans.
Cc: Darren Hart <dvhart@xxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
CC: Zhang Rui <rui.zhang@xxxxxxxxx>
Cc: Andreas Mohr <andi@xxxxxxxx>
Cc: Javi Merino <javi.merino@xxxxxxx>
Acked-and-tested-by: Borislav Petkov <bp@xxxxxxx>
Signed-off-by: Peter Feuerer <peter@xxxxxxxx>
drivers/platform/x86/Kconfig | 3 ++-
drivers/platform/x86/acerhdf.c | 36 +++++++++++++++++++++++++++++++-----
2 files changed, 33 insertions(+), 6 deletions(-)
diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index a2eabe6..c173266 100644
@@ -38,7 +38,8 @@ config ACER_WMI
tristate "Acer Aspire One temperature and fan driver"
- depends on THERMAL && ACPI
+ select THERMAL_GOV_BANG_BANG
So we use select sparingly as it does implicit things.
I checked the THERMAL_GOV_BANG_BANG Kconfig entry, and the help says acerhdf
already depends on it (which it doesn't appear to). Any particular reason to add
select here instead of adding it as a depends.
Why did you drop THERMAL?
I had it like this in my first version of patches:
+ depends on THERMAL && ACPI && THERMAL_GOV_BANG_BANG
But after some discussion with lkml community we ended up with the select line and dropped THERMAL dependency, as it is implied by THEMAL_GOV_BANG_BANG. I'm not so experienced with Kconfig, so I must rely on the statements of the community in this case.